Some error while posting.
Tonearm mount on the plinth or on Pillar ?
Folks,
I am looking to buy a custom built turntable from Torqueo Audio (http://www.torqueo-audio.it/). They have two models, one with a wide base plinth where the tonearm would be mounted on the plinth (as usual) and the second is a compact plinth where they provide a seperate tonearm pillar to mount the tonearm. According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT. My concern is whether seperating the tonearm from the plinth would result in a lesser coherence in sound ? Isnt sharing the same platform results in a more well-timed, coherent presentation ? Any opinions ?
I am looking to buy a custom built turntable from Torqueo Audio (http://www.torqueo-audio.it/). They have two models, one with a wide base plinth where the tonearm would be mounted on the plinth (as usual) and the second is a compact plinth where they provide a seperate tonearm pillar to mount the tonearm. According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT. My concern is whether seperating the tonearm from the plinth would result in a lesser coherence in sound ? Isnt sharing the same platform results in a more well-timed, coherent presentation ? Any opinions ?
139 responses Add your response
| Post removed |
Dear Pani, The answer to this one depends on who you speak to. The Cartridgeman, for example, swears by completely separate platforms i.e. motor/turntable/arm pillar for the air-bearing linear arm. For good measure he even decouples the Classic cartridge with a "spacer". Although I like the Cartridgeman’s products a great deal I cannot reconcile the operation of the tonearm without close coupling (i.e. the so called "closed loop") but it wouldn’t stop me buying them ;^) Technically, there might still be a closed loop even for the "separatist" approach except that the final connection is by means of a shelf or a platform. Then any variability would be introduced by whatever is being used to support/level the various elements e.g. 3 solid spikes relative to whatever material the supporting surface was made of. Provided one could guarantee the T/T & tonearm stay in precise relationship at all times I wouldn’t see a problem. Trouble is that the tonearm is by nature constantly manipulated and messed around with by the User so personally I’d feel uncomfortable if it wasn’t locked down and immovable..... Just my opinion though.... :( |
Other posts here include testimony by folks who utilize "naked" plinths (none at all, only support columns for the motor unit) with separate tonearm pillars. They rave about their results. I've not tried that but I remain skeptical. Just consider how critical the accurate set up alignment is for the stylus, then ask yourself how that can be achieved when the cartridge/arm mounting is not "fixed" relative to the platter/record? So I agree with moonglum. Plus I live on the West Coast where we are subject to earthquakes, some of which go unfelt. I don't want my tonearm "dancing" around somewhere close to the correct position. |
According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT.This statement from the original post is false. The problem you are up against is an engineering issue and is very similar to that of the steering and suspension in a car. Any looseness or flex in that system results in dangerous or scary handling! Now in a turntable how it plays out is that instead of being scary or dangerous, it works out as a coloration: the platter must be as tightly coupled to the plinth via its bearing as possible, in turn the plinth must be absolutely rigid and acoustically dead while coupling the platter bearing to the base of the arm (which in turn should have no play in its bearings). Any divergence from this formula results in coloration. The reason is simple: if the platter has any other motion other than rotation (for example a slight up and down that might be imparted from the plinth due to room-borne vibration), if there is any difference between that and the base of the arm the cartridge will compensate (since the stylus has to stay in the groove) with stylus motion and therefore a coloration. So if the arm is sitting on a separate structure from the plinth, it is open to motion in a different plane and/or frequency as opposed to the platter and plinth. You really want it to move in the same plane and frequency as the plinth so that whatever that motion is can't be interpreted by the cartridge. I am often amazed at how poorly understood this concept is. |
czarivey, As I stated, some quakes are not felt, but they occur and are registered. So I may possibly have been listening to vinyl sometime while one happened. But you missed my point, unless you were just being humorous. The danger would be for my arm position to be shifted during that event so it would be out of alignment the next time I did play a record. I'd prefer that relationship (platter/record to arm/stylus) to be locked in place. And thanks for weighing in with logic Ralph. |
On the topic of quakes it's not just earth movement from quakes but also the rumbles and vibration of passing vehicles as well. Where I live in an urban setting I have a soundproofed room but can still feel big trucks passing as the whole building shakes (as it is designed to do in a quake zone). Hence my recent investment in Townshend Seismic isolation which I'll post a thread on shortly -- you can check the attached for details on quakes, and I can certainly affirm that the podium works as promised! http://townshendaudio.com/PDF/Earthquakes%20on%20Hi%20Fi.pdf |
True Ralph. What you describe is an ideal situation but it is a fact that tonearms & plinths, even when locked rigidly together, resonate differently e.g. tonearms will have multiple resonant peaks which are not shared by the turntable which help to give each tonearm its unique sound. In a perfect world they would be in perfect harmony. It seldom detracts from the enjoyment of the music we eventually hear. |
Hi Pani It’s important imo, to remember that the plinth is the lowest member of a base. When setup in this fashion the shelf holding "all the goods" becomes the plinth. I went down this road many years ago, putting a tonearm on an isolated armpod/pillar. I was curious, it was fun, and it involved a lot of learning. I took the idea further using symposium roller block jrs., and a VPI JMW 12 tonearm. The original idea came from a Greek audiophile. I had so much fun I wrote a review of it, with a short youtube. https://www.youtube.com/watch?v=HSZSzxnN1mg Going by memory I can tell you that the cartridge used was very high compliance, Dynamic Compliance: 50 x 10-6cm/Dyne and when set up in the traditional way sounded terrible on this tonearm. But when set up like this; well you listen. Pryso Pryso I am thinking the symposium setup might actually work for an earthquake, but I have no experience. I have experienced only a couple of shakes in Ontario, barely noticeable . What do you think ? Chayro - I thought that was an interesting analogy. Some have tried to use the analogy of two boats floating next to one another. This analogy doesn’t work for me. An analogy that works better - I put in a heavy 20 foot long dock in the water one summer, and was so happy with the accomplishment I danced on the end of it. It barely moved. |
I think I may need to offer a clarification on my reference to earthquakes. At least for those living with more stable terra firma who don't experience them. My concern is not so much for movement while I'm listening (touche czarivey), although that is possible, but rather for shifting of the arm position whenever a quake occurs. Since the table and arm (including bases) do not have the same mass their likelihood and degree of movement will not be the same. And I may not even know the quake happened, and so to recheck alignment, but my system may not then sound "right" afterwards. Of course as others mentioned there are other earth borne vibrations to be concerned with. Is there a major highway nearby? Any bus or large truck traffic? Is there construction close to you? And those are all external forces. How stable is your turntable platform to begin with? |
There is a long thread on this subject started by Halcro, in the context of which he refers to the idea of separating arm pod and plinth, which he favors, as "Copernican". I vigorously disagree with him; I agree with Ralph (Atma-sphere) that the two should move as one. However, I do agree with Halcro on many other subjects, and I consider him a friend. Ergo this point is no longer worth arguing about. He and anyone else can do as they please, and I will do as I please. We'll both be happy, I am sure. I will just say one thing: Moonglum, your statement that the tonearm and plinth resonate separately even if they are locked rigidly together is kind of an oxymoron; if they resonate separately, then the goal of tying them together rigidly has not been met. And in fact, I think a lot of designs are imperfect like that. It takes a very substantial structural linkage to achieve the proper resonant unity. I also think that if you bolt an outboard armpod to a rigid shelf and also bolt the plinth to the same shelf, you are doing the right thing. The last photo I saw of Halcro's TT101 set-up looked to me like he was doing that; it looked excellent in fact. |
| Post removed |
Dear Lew, You're misquoting me. I said resonate "differently" not "separately". A subtle distinction but a real one nevertheless. Do you disagree that tonearms resonate in the manner I described? I think you're taking an over-simplistic view of the design brief. A tonearm will have a natural level of decoupling (point contact through bearings or a single point bearing). Even if the T/T chassis is heavier than an anvil there is a limit to the extent that such coupling can damp the behaviour of the arm(?) Look at it another way, if such behaviour did not exist it would be pointless selling clip on dampers for tonearms, or using silicone fluid to help control it even in some of the finest engineered tonearms ;^) A more graphic example is if you clenched a tuning fork in your fist, vibration would be suppressed. If you hold it in the proscribed manner it will operate but it's important to note that a massive object (you) is nevertheless still gripping a non-massive object (the tuning fork). I don't know Halcro's outboard system but I haven't condemned any approach in fact I seem to remember endorsing what Ralph said ;^) Kind regards, |
Dear @ pani: 23+ years ago I was looking how to improve the quality sound on my analog rig. I owned and own two Denon TTs: DP-75/80 and Technics SP-10s. I took the alternatve to change both Denon TT plinths and instead to following using the wood plinths I start to use one green marble and one beige onyx plinths ( around 45 kg each one and beatiful looking " guys ". I still have it. ). The overall quality sound improved by a wide margin. Two years latter I decided to try a new knd of plinth and the new plinth was: USE NO PLINTH AT ALL, mounting the tonearm in a separate " tower/pillar ". Again it was an improvement but not so big as before with the stone plinths. For me/in my case was there when the overall " naked " concept rised and years latter I brought here at Agon and other forums in the net. I used in the SP-10s too. The theory behind the Atmasphere pst is right and tha is not under discussion but try to help yu in your question. Till today I never heard and never was and is any concern that with a separte tonearm mount tower the quality sound performance losted some kind of coherence or well-timed coherence presentation. In my case I had no choice for Denon/Technics TTs, I was " obligated " to take the naked " road " that IMHO works really good it does not maters what theory say. I think that as everything in audio exist trade-ffs here, at one side is the theory and at the other side the sound qaulity level performance in the non-plinth alternative. Till today I did not and don’t read it a real/fact through listening scientific tests that confirm any single advantage to that theory. So leave it at rest and decide what you can think is your preference: though your audio distributor you can listening both alternatives and decide about. Btw, It’s easy to measure if the frequency response, phase and amplitude of the TT ( plinth/motor/platter spinning, etc. ) is exactly the same at the tonearm directly because every kind of " joints " where those vibrations has to travel till achieve the tonearm it self can change. Kuzma, between others, choosed to design some of its TT models with an external tonearm tower and I never read any customers compliant about. In audio be too dogmatic not always gives the better results. Btw, that youtube link can say many things but can’t prove something scientific. Seems to me that the TT in that video is a Technics that with its own plinth is really " terrible " and with that Sonus cartridge/VPI the resonant frequency is around 4 hz. That Technics plinth and the resonant tonearm/cartridge frequency are against in between. My opinion is try to mantain the phono cartridge as aisle as we can, at maximum of the posibilities. Any kind of vibration/resonance produce and increment many diferent kind of distortions that goes against the quality sound level. An external tonearm moun ting tower is a way to aisle ( in some ways. ) the phono cartridge and does not maters if the external power is seated in a different platform that the TT. Regards and enjoy the music, R. |
Moonglum, It's the tonearm bearing that must be firmly coupled to the turntable bearing. Yes, some tonearm bearings have more or less "play" with respect to the arm wand/headshell/cartridge, but at least there should be no wiggle room between the tonearm mount which embraces its pivot and the platter bearing. Pardon me if I misquoted you, but is there a real difference between resonating "differently" vs "separately"? Anyway, my opinions on this issue are well known; no point repeating myself. Others can think differently, and I am sure that the earth will remain in orbit regardless. |
Glad no one took my last comment about T/T designers seriously ;^) I was joking of course. I actually have the highest respect for what they're trying to do. It's an unenviable task and by doing it they're only going to please some of the people some of the time. No problem, Lew. I agree the Earth isn't going to disintegrate due to the nuances of definition of 2 words. Since you did ask, "separately", to me, means without touching while "differently" means they can be touching. That's all. Yeah, the main causes of wiggle room that I can see are the main bearing and tonearm bearing/s unless you're referring to flexure in the chassis & armboard(?) But the point I was making is that it's the overlapping contact area of those bearings that would determine how effectively the 2 are locked together i.e. from a damping perspective. Since you are relying mainly on those bearings to commute/handle vibration it can never be an effective way to damp the tonearm. By nature, the bearings must try to be as zero contact as possible rather than act like a 6" nail through 2 pieces of wood. Seems to me it's a classic "Catch 22" situation? |
pani here is a pic http://www.sonicscoop.com/site/wp-content/uploads/2013/04/stocklathe.jpg Pani fwiw. I still do own three tables but only use one. Two of the three tables Verdier La Platine (main) and my DIY SP10 MKII (up to version 8?) from years ago have pillars/pods for the tonearm which is bolted into the plinth. The Platter structure is bolted into this same plinth. The Brass Pod on my SP10MKII is very heavy its not going anywhere but it was very easy to shoot a bolt in from the bottom, and I use only one tonearm with it so I bolted it in. https://goo.gl/photos/1tpMKeEahAdXFEN38 The third table is a Jean Nantais table. I don’t know how familiar you are with his designs. http://www.idler-wheel-drive.com/ Going back if I recall, Jean is very much in favor of a very rigid coupling. But even he recognizes the problems with bolting a tonearm to a plinth that is shared with a spinning platter/bearing/motor. All his designs have "voids" where the tonearm is mounted to lessen the effect of the plinth itself. This void extends down through the whole 100 lb plinth on mine. I think the plinth would weigh quite a bit more if the two voids for two tonearms were filled in. Raul - you misunderstood the intent/purpose of the youtube video that my 16 year old son budding audiophile at the time took. He is now 21 - where does time go? This was an experiment/ a test during an Audiophile Phase. I indicated that this tonearm/cart/ in the traditional setup the sound was terrible; but the armpod setup with the roller block jrs. significantly changed resonances/vibrations (which vinyl play is all about) for the better. The focus was the symposium roller block jrs. on an armpod; and the technics table has only a skeleton plinth. Not sure how you came up with a stock plinth ? Pryso - I think at this point I am willing to put up with some earthquake shakes if it meant good year round weather. Can you imagine that armpod on the roller block jrs. if not being used moving back and forth, during a quake - like the buildings themselves. moonglum great vid. It could be planted on many audiophile forum threads. :^) I use oil in the bolt threads of the pods before the bolt is inserted. Cheers |
Theories are great..... I know of tonearm designers who can convince you that Uni-pivots are theoretically superior to gimballed tonearms.... But hey....they can both work fine. I know some turntable designers who can convince you that belt-drive high mass turntables are theoretically superior to direct-drive and idlers...... But hey...they can all work just fine. I know some cartridge designers who can convince you that MC is theoretically superior to MM.... But hey...they can both work fine. Yep....I just love theories 😎 |
Dear @lewm: """
my opinions on this issue are well known; no point repeating myself. Others can think differently.... """ are those opinions based or with foundation on first hand experiences in your own audio system through several tests with and with out same tonearm/cartridge? If yes I would like to hear your confirmation about and trade-offs you experienced and if not maybe is time to have the stand alone tonearm tower to confirm or not your opinions, this could gives more value to those opinions. Don't you think? Regards and enjoy the music, R. |
No thanks, Raul. This is not to say you and Halcro are "wrong". Really, really; I don't care. I am sure that your system, and Henry's system too, are wonderful. Both of your systems differ from mine in very many ways, other than turntable/tonearm linkage, and it is not incumbent upon me to try out all the variations in order to say that I prefer what I have. Over 40 years, I've been there and done that. The OP asked for opinions. I have stated my opinion and the theoretical why of it (and so has Atma-sphere in a more elegant treatise), and that's all I care to do on this subject. Like I also said, I fully approve of Halcro's current TT101 set-up, even though he may believe we are at odds. (Your set-up may be just fine by me, too. I haven't seen any photos, so I cannot really say.) Like you say, enjoy the music. I certainly am. |
Chris, thanks for the update on your SP-10 Mk 2. Your idea to mount your arm on a separate pillar and then bolt the pillar to the base (plinth), same as for the motor unit, is similar to the direction I've moved. That is sort of a "middle ground" between a naked table and one that is directly connected. ;^) My thinking is by not mounting the arm and motor unit to the same top layer of whatever material in the plinth but still have a fixed connection, any energy transfer between the two will need to travel a greater distance and (likely) through different materials, and thus be absorbed or at least diminished. Now after multiple false starts I need to find someone local with the proper tools to build it for me. |
I’ve seen many arm pods, but this one ( TH-100) is the most exotic solution along with this heavy TM-10 metal plinth by JoJo Toho Machine (i know nothing about this company). It’s called Toho Player base System for Technics SP-10mk2, also for Victor and Denon turntables. This design looks as solid as Neumann cutting machine imho. I wish i could get time machine to buy this Toho Base for my SP10 There is one for Halcro’s Victor table too (more elegant than naked victor imho) How do you like it ? |
Lewn, it looks very attractive, i’m afraid this is vintage advertising. There is only phone number on the poster! Someone should call TEL/ (03) 908-0320 :)) Who can read/speak japanese? Prices for Toho Player base Systems: TM-10 (Technics) plinth weight 27kg, price 230 000 Yen +TH-100 Arm base weight 5.9kg , price 88 000 Yen and something called M-3, m4, m5, g23, g30, g41 (additional armboard?) starts from 12 000 to 68 000 Yen! TC-20 (Denon) plinth weight 29kg, price 230 000 Yen TV-30 (Victor) plinth weight 24kg, price 210 000 Yen +TH-80 Arm base weight 7.6kg , price 33 000 Yen and p23, p30, p41 (additional armboards?) for 6 800 Yen If it was made in the 80s then the price is tough! |
In a typical cutting lathe is the cutting arm mounted on the same plinth as the platter or is it on a platform ?The lathe platter and the cutter are mounted rigidly in the same assembly. Ours is made of cast-machined stainless! That assembly in turn resides on an anti-vibration platform which in turn rests on a table with adjustable pointed feet. By having the cutter and platter rigidly coupled, vibration entering the system does not get cut onto the LP. The same principle must be applied in playback to insure a lack of coloration. Any deviation from this formula will result in -wait for it- deviation (of the stylus) and will result in coloration. Whether that coloration is heard and accepted as such by the operator is another matter entirely! |
That TOHO stuff looks very interesting! More info on TOHO: https://audio16.com/2013/10/11/copernicus-was-right/ http:///audiocirc.com/2014/03/12/more-than-a-tonearm/ http://20cheaddatebase.web.fc2.com/needie/NDTOHO/TOHO.html http://www.vinylengine.com/library/toho.shtml Looks like they gave up on audio, but are still in business doing camera things. |
Interesting ToHo stuff. I was aware of their tonearm pods (as Thuchan has one)...but I never saw their turntable cast-iron supports before. Looks quite similar to my new support 👀 http://i.imgur.com/ddKNHVx.jpg Interesting cutting lathe here http://i.imgur.com/GB8oq5U.jpg |
***Now in a turntable how it plays out is that instead of being scary or dangerous, it works out as a coloration: the platter must be as tightly coupled to the plinth via its bearing as possible, in turn the plinth must be absolutely rigid and acoustically dead while coupling the platter bearing to the base of the arm (which in turn should have no play in its bearings). Any divergence from this formula results in coloration. This concept is a gross oversimplification and isn't thought through. Airborne vibrations will be imparted to the platter (record), plinth, and arm at roughly the same time. There will be a delay as these vibrations are then transmitted from one to the other. This results in additional smearing/coloration. It could also result in greater amplitude and additional coloration. This is not better. It's worse, assuming the pod approach is well done and resists cross coupling. There will still be some cross coupling through the base, but it's less likely to produce cross coloration if the base resists vibration transmission and the pods are mass coupled. It's a fallacy to assume that vibrations appearing at the main bearing are best transmitted to the arm. ***According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT.*** No good reason to assume this is false. Regards, |
It's remarkable how durable is this controversy over separate vs linked and how vehement are the opinions, one way or the other. Pryso and Chris, for me, bolting the outboard arm pod to the plinth fits into my philosophy. Fleib, your statement: "There will be a delay as these vibrations are then transmitted from one to the other. This results in additional smearing/coloration. It could also result in greater amplitude and additional coloration.", is for me a reason why optimally the linkage must be extremely massive and rigid. Isolating the two elements does not seem to me to be a solution to the problem you cite. Most ordinary tt plinths don't cut the mustard on the criterion of linkage. Take a look at the underside and "armboard" of a Kenwood L07D, if you want to see an example of what I think is a good way to establish proper connectivity. Also, take a look at a modern Galibier turntable for another example. By the way, I have long been of the opinion that a "plinth" that minimally extends out beyond the perimeter of the platter, IOW, a circular but massive plinth a la Halcro's latest or Thuchan's new slate plinth for the TT101, or the Galibier tt's, is optimal. (There are many more commercial products built this way.) I suspect that the older traditional rectangular plinth which provides a large open flat surface out beyond the platter can induce colorations by reflecting sound produced at the stylus/LP interface back at the stylus, but it's just a guess. Thus a "pod" for the tonearm is fine with me, but it should be very positively linked to the support structure for the tt bearing, if not directly to the bearing. |
Lewm, What is "proper connectivity" ? The physical (mounting) relationship between platter and arm must be maintained. The plinth or chassis must be heavy, rigid and not prone to transmit vibrations. Why? So vibrations or movement of the bearing does not get transmitted to the arm? So these vibrations get transmitted and the arm moves in concert with the platter? It's nonsense. Regards, |
Dear @lewm: """
It's remarkable how durable is this controversy over separate vs linked and how vehement are the opinions, one way or the other. """ Either, by theory or real tests, some way or the other almost all of us talk about " colorations/distortions " . The " theoretical " people ( like you ) can't prove those theories with out first hand real tests/measurements and the ones ( like me ) that already tested and made several comparisons in between TT integrated arm pillar and stand alone tonearm pillar neither have scientific measurements of what we are listening or not but the " testers " have a clear adevantage over the theoretical gentlemans: we can attest a " better/lower colored " quality sound level that for example you have not and can't imagine. As I posted for a theoretical opinion can has value it needs first hand experiences in each one own audio system, if not your opinions are just: useless. Now, is't easy to measure ( through a scientific methodology. ) the theoretical " additional colorations/distortions " you, atmasphere and the theoreticals ones supports?, I think not for any one. We have to think how to aisle the specific " colorations/distortions " created in specific by the sole integrated arm pod variable and the stand alone arm pod variable against all the other variables ( colorations/distortions. ) involved in the end result when the sound waves comes in the air and goes through our ears. Who of you can make the measures that with certainty. So and till today the best is to listen it as some of us did it or still do and with all respect for people like you just forgeret on this audio subject. There are people like you that are willing to try it and some of them will try through the time but you are not even willing to try but always give the same theoretical statement with no single fact that prove it and that's why I posted is useless and with low value opinion. I know, any one is free to give his opinion: valid or not. So you can go on with. Anyway, stand alone tonearm pod or not in both " configurations " exist distortions of many kind. Wich configuration puts us nearer to the recording?, this's the question and main subject. No one is the Bible's boss. Regards and enjoy the music, R. |
Raul, You are conflating opinion with fact. The fact that you listened to your turntable and your tonearms in a variety of set-ups, and by your own admission made no measurements but merely judged the various configurations subjectively, only adds up to.... your opinion of what sounds "best". Modern principles of science and experimentation show conclusively that unblinded testing of this sort is never free of bias. On the other hand, I may be accused of bias too, but is it not true that one wants no motion at the stylus tip, ideally, except that which is induced by groove undulations deliberately introduced during the encoding of music? (I am hoping you would agree with that premise.) Then, if so, why would one want to take a chance on movement of the tonearm pivot with respect to the turntable bearing/platter/LP surface that could be due to the differential effect of forces acting on one and not the other or both to different extents? I cannot think of a reason why that would be acceptable, if it can be avoided. That's the theory on which I base my choices. In this case, I think it is YOU who are subconsciously preferring "distortions". I am completely of the "live and let live" philosophy. Doing what you like is perfectly OK with me; just don't turn around and accuse ME of being deluded. There is no science at all in your approach. If you want to do some science, take some relevant measurements using sensitive instruments. By the way, if you are still using those Audio Technica pucks under your turntable, then even Halcro and the other Copernicans have left you behind, because they have come around to using rather massive cradles for both the turntable and the arm pod. Enjoy the music. |
Anyway, stand alone tonearm pod or not in both " configurations " exist distortions of many kind. Wich configuration puts us nearer to the recording?, this's the question and main subject.This is actually easy to measure! We do it with a silent disk, cut on our lathe, which is much quieter than normal vinyl. All we have to do is place the turntable in a room with speakers playing loudly and then measure the output of the cartridge. The fact that turntables that employ a separate arm pillar are more noisy then 'tables with a proper plinth is easy to see on the 'scope. What is the vertical angle being cut into the disc where you work ?In theory the ideal is 92 degrees. In practice, its **about** 92 degrees. This is so because not all cutting styli are identical. They only last about 10 hours before no additional heating of the stylus will keep them quiet, so they have to be replaced. This is a bit of a procedure! Once in place the cutterhead has to be set up from scratch. This is because the previous settings that worked with the first stylus are not going to be the same with its replacement. The technique for setting up the stylus involves a lot of measurement, but an exact rake angle is not actually specified in any of the manuals. What is important is that the stylus be able to cut a silent groove. So after making an adjustment that's exact what we do, then play it back and measure the noise floor. When the noise floor is the noise of the electronics and not the surface then we know we are in the ballpark. From this you can correctly infer that no LP is cut at exactly 92 degrees, instead, all LPs are cut at **about** 92 degrees. Its an approximation that results from the way the cutting stylus itself (which is made of sapphire) is cut. |
Atmasphere, ***This is actually easy to measure! We do it with a silent disk, cut on our lathe, which is much quieter than normal vinyl. All we have to do is place the turntable in a room with speakers playing loudly and then measure the output of the cartridge. The fact that turntables that employ a separate arm pillar are more noisy then 'tables with a proper plinth is easy to see on the 'scope.*** This statement is unexpected and seems counterintuitive, at least to me. Could you describe the tables measured? If you've seen photos of Halcro's TT101, do any of the measured tables reflect that level of isolation? Regards, |
As Fleib writes.....which tables have you measured? This would seem like excellent scientific data and would resolve this argument once and for all. Could you please list all the tables, arms and cartridges and what they were sitting on Atmasphere? Photos would be good here. And can you upload the frequency print-outs for each one? Lastly....how do you discern the different contributions of arm, cartridge, table, drive system, arm support and isolation provisions in the data? |
Dear @atmasphere: """
This is actually easy to measure! We do it with a silent disk, cut on our lathe, which is much quieter than normal vinyl. All we have to do is place the turntable in a room with speakers playing loudly and then measure the output of the cartridge. The fact that turntables that employ a separate arm pillar are more noisy then 'tables with a proper plinth is easy to see on the 'scope. """ Good that for you it's easy task. I think that your measure is not exactly what happens during playback because you did not use a recorded LP and we want to know what it's happening during playback in real day by day listening conditions. Now,: speakers playing loudly?. 95 db, 90 dbs, 100 dbs? why only playing loudly? We need to have information as day by day real as we can not over diferent conditions. Even playing " loudly " maybe that stand alone tonearm pod was not the " ideal " one because its choosed build material, weight or damping or whatever. Cartridges are all very sensitive are a microphone with high sensitivity but each cartridge is affected in diferent way for sound waves or any other kind of vibrations/resonances and depends in what tonearm are mounted. There are several variables that are inside the whole subject. The other gentlemans have too many questions as they posted. Yes, is very easy but in reality what you did it can't gives to us " one and for all " the scientific answer. Maybe you have to reset the methodology and take in count not only those variables we posted here but many more that has influence in the whole subject. Good that you can take this task because " one and for all " can gives us the answer we are looking for. Regards and enjoy the music, R. |
Raul's tongue and cheek is on the money. The variables are endless. Drives, motors, materials, size , shape, weight etc etc etc... What would be nice is someone with 1st hand experience with a table that has a arm attached and a pod that can go on other side. Of course it would have to same arm, wire, cart etc. Of course one might find that one cart might like it one way while another the opposite. Then if one finds a difference now the subjective equation comes into play!!! What would also be nice if a person with some real physics background in vibration and frequencies would chime in. My quess in regards to the connection issue moving the pod around would be, I can not imagine a cantilever, at 2.5 grams, moving a 30lb plater or a 5/10 lb pod. In regards to pod overall movement build a jig to get close and dial it in with the overhang. I do not have a dog in this fight. I do have two tables and 4 arms. 3 pods and 1 plinth attachment. Can interchange almost everything between them. Have two diy tonearm, which are very close, so before it is over will do like I stated above ,one on plinth one on pod same table etc. Enjoy the ride Tom |
This statement is unexpected and seems counterintuitive, at least to me. Could you describe the tables measured? If you've seen photos of Halcro's TT101, do any of the measured tables reflect that level of isolation? Could you please list all the tables, arms and cartridges and what they were sitting on Atmasphere? Photos would be good here. Good that for you it's easy task. I think that your measure is not exactly what happens during playback because you did not use a recorded LP and we want to know what it's happening during playback in real day by day listening conditions.We ran this experiment using our lathe. The reason was we wanted to install a 12" Triplanar on the machine so we would not have to move the lacquer to a different turntable once in place- to test, simply place the tonearm on the cut. The easy way out was to install the arm on a pillar. We found out really quick that was not the best move. Now you have to understand several things here- first, the lathe is mounted on an anti-vibration platform that is rather massive, designed specifically for the lathe. That in turn sits on a custom table with adjustable points for feet. The entire arrangement has to be by definition rather dead, else sounds in the environment can affect the cut. What we discovered is that the arm mounted on the pillar was giving us more noise than the same lacquer played back on a Technics 1200 sitting nearby. IOW, it was not suitable for actually telling if our cut was truly silent, set up in this fashion. By coupling the arm directly to the plinth in which the platter bearings reside the issue was solved. Apparently even though a very effective anti-vibration platform was in use, it could not prevent the arm from moving in a different plane from that of the platter (which is the failing of pillars generally speaking, per my first post above, should anyone care to understand the engineering principle in layman's language). This ultimately required that we machine an arm mount that mounted to the plinth rather than the platform. We made our measurements using the phono equalizer in a Tascam mixer board, read by an Tektronics 465 oscilloscope. I hope this gives you some idea of how easy it is to measure this! As to sound pressure- we get about 90-95db of noise going on when mastering. The vacuum system is enclosed in its own chamber, but still makes noise when in operation. Now I understand this is bad news for some and as a result there will be those that think that somehow these principles don't apply to their machine. It is true that I did not make the measurements on anything other than our lathe, but if you think the engineering principle is somehow different, or that the lathe is somehow noisier than a conventional turntable (while at the same time somehow perfectly capable of turning out cuts that are so quiet that essentially the playback electronics are the noise floor no matter how quiet) you would be mistaken, check with Mr. Occam on that one. It is of no consequence whatsoever that we used a silent groove for this test. A groove with modulation will still experience the same noise and colorations if the arm is anchored to a point that is able to move with respect to the platter. This is not a difficult principle to understand; IMO the resistance to it springs out of the cost of some of the machines guilty of this engineering flaw- its an inconvenient truth (especially when you consider how much harder it is to make a plinth for the platter and the arm). FWIW, the lathe is not a cheap machine either; if we were to put it up for sale in its present state (functional tested used stereo cutting system) it would be going for over $30K. If it were new it would be pushing 6 figures. Out of necessity it has far more precision in its construction than most turntables. Now I want to make something very clear. I'm not saying a system with a separate pillar can't sound **good**. What I am saying is that if the arm mount is integrated into the plinth it will be lower noise and have less coloration, i.e. it will sound **better**. |
Sorry Atmasphere, I missed the point about the Triplanar and the Technics 1200. I don't see how attaching the tonearm to the plinth can affect the 'noise'? Surely the 'noise' is a function of the isolation, the tonearm pod mass, fixity, density and material selection as well as the tonearm rigidity. There are some who are not fans of the Triplanar with regards to its performance in these areas.....but reaching conclusions about 'noise' when using different tonearms does not seem paticularly scientific nor conclusive. |
This seems like an anecdote - interesting but lacking specifics. What about the arm pod details? First we're told, **All we have to do is place the turntable in a room with speakers playing loudly and then measure the output of the cartridge.** Then, **As to sound pressure- we get about 90-95db of noise going on when mastering. The vacuum system is enclosed in its own chamber, but still makes noise when in operation.** All of the above? You're checking cuts while this vacuum system is in operation. There are also vibrations coming from the vacuum motor which is making 90 - 95dB of noise while in its own chamber? The obvious question - did the separate arm pod have the benefit of the isolation platform as the platter? I'd also like to remind everyone, assuming the Technics 1200 was a MKII or later, this table was designed to play in extreme noise, in excess of 100dB is not unusual. It would be interesting to see a more scientific test. If a plinth mounted arm is quieter, at what room SPL does it become so, and for exactly what plinth, arm, and pod. fleib |
